Proteopedia:Previously Featured Articles

The Ribosome - Featured Oct. 18th, 2009 - Current Date
 By Wayne Decatur On October 7th, 2009 the Nobel Committee announced three structural biologists would share the 2009 Nobel Prize in Chemistry for studies of the The Ribosome. The ribosome is the machine in your cells that accurately and efficiently decodes the genetic information stored in your genome and synthesizes the corresponding polypeptide chain one amino acid at a time in the process of translation. Venkatraman Ramakrishnan of the M.R.C. Laboratory of Molecular Biology in Cambridge, England; Thomas A. Steitz of Yale University; and Ada E. Yonath of the Weizmann Institute of Science in Rehovot, Israel share the prize for the first atomic-resolution structures of the two subunits that come together to form an active ribosome. These structures are considered landmarks for the fact they showed clearly the major contributions to decoding and peptide bond synthesis come from RNA and not protein, as well as for the sheer size of the structures determined. These structures represent tour-de-force efforts in understanding fundamental processes in every organism on earth and will have direct impacts on how we fight pathogenic bacteria in the immediate future. Shown here (restore initial scene) are both subunits of the ribosome, as well as mRNA and tRNA that bind in the complex during the process of translation. Read more....

Avian Influenza Neuraminidase - Featured May 2nd - Oct. 18th, 2009
 By Eric Martz H5N1 bird flu has seemed a likely pandemic threat for decades, but the first new influenza virus to emerge as an imminent pandemic threat in the 21st century is H1N1 swine flu. The drug oseltamivir (Tamiflu&reg;) inhibits flu neuraminidase, a component necessary for virus spread, in susceptible flu strains. Luckily H1N1 swine flu is susceptible (at least in early May, 2009). The development of oseltamivir was guided, in part, by crystallographically determined structures of flu neuraminidase. Neuraminidase is a homotetramer, shown with oseltamivir bound (restore initial scene ). Here is one catalytic site. Oseltamivir was designed to fit N2/N9 (neuraminidases from other strains of flu). Serendipitously, it also fits N1, doing so by pulling one side of the binding site against itself (induced fit). The most common mutation in N1 that confers resistance to oseltamivir is H274Y. The mutant tyrosine prevents oseltamivir from fitting, but still allows zanamivir (Relenza) to bind. Read more....

Poly(A) Polymerase - Featured Dec. 15, 2008 - May 2nd 2009
 By Eran Hodis Poly(A) polymerase binds specifically to ATP and adds it the end of a mRNA chain. This structure contains an oligo(A) polynucleotide with 5 nucleotides, an ATP molecule, and a magnesium ion. … In the 3D figure, the enzyme is shown as a blue backbone, the RNA chain in yellow, the ATP in red, the Mg++ in green, and ALA154 in magenta. Several mechanisms are used to achieve the specificity for ATP. The Mg++ is coordinated by ASP100 and ASP102, and the Mg++ coordinates with the phosphates of ATP, positioning the nucleotide in the active site. The adenine base is sandwiched between the terminal base of the RNA (in yellow) and VAL234 (in cyan). Read more...